U.S. patent application number 10/081057 was filed with the patent office on 2002-09-19 for pseudo-random pattern transmission apparatus.
Invention is credited to Yoshida, Hirokazu.
Application Number | 20020131450 10/081057 |
Document ID | / |
Family ID | 18906613 |
Filed Date | 2002-09-19 |
United States Patent
Application |
20020131450 |
Kind Code |
A1 |
Yoshida, Hirokazu |
September 19, 2002 |
Pseudo-random pattern transmission apparatus
Abstract
A pseudo-random pattern transmission apparatus which has
software processing means 1, storage means 2 for storing a
pseudo-random pattern, transmission memory 3 for storing a
plurality of packets comprising the pseudo-random pattern inserted
in sequence into payload parts of a continuous frame of digital
signal, an idle sending processing section 4 for calculating the
number of inserted idle bytes calculated in response to the
specified transmission rate of the digital signal, and transmission
control means 6 for alternately executing transmission of a
plurality of packets from the transmission memory and transmission
of idle bytes from the idle sending processing section to a digital
line 7.
Inventors: |
Yoshida, Hirokazu; (Tokyo,
JP) |
Correspondence
Address: |
SAMUEL BORODACH
Fish & Richardson P.C.
Suite 2800
45 Rockefeller Plaza
New York
NY
10111
US
|
Family ID: |
18906613 |
Appl. No.: |
10/081057 |
Filed: |
February 21, 2002 |
Current U.S.
Class: |
370/474 ;
370/392 |
Current CPC
Class: |
H04J 3/1617 20130101;
H04L 69/166 20130101; H04L 69/16 20130101; H04L 69/168
20130101 |
Class at
Publication: |
370/474 ;
370/392 |
International
Class: |
H04J 003/24; H04L
012/28 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 21, 2001 |
JP |
P.2001-044660 |
Claims
What is claimed is:
1. A pseudo-random pattern transmission apparatus comprising: a
pseudo-random pattern storage section adapted to store a
pseudo-random pattern; a transmission memory adapted to store a
plurality of packets which is constructed by inserting the
pseudo-random pattern in sequence into payload parts of a
continuous frame of digital signal; a software processing section
having an idle sending processing section adapted to calculate the
number of inserted idle bytes in response to a specified
transmission rate of the digital signal; an idle sending section
adapted to send an idle byte; a transmission control section
adapted to alternately execute transmission of the plurality of
packets from the transmission memory and transmission of idle bytes
from the idle sending processing section to a digital line.
2. The pseudo-random pattern transmission apparatus according to
claim 1, wherein the digital signal is an IP packet.
3. The pseudo-random pattern transmission apparatus according to
claim 1, wherein the digital signal is a PPP frame.
4. The pseudo-random pattern transmission apparatus according to
claim 3, wherein whole IP packet forming a part of the PPP frame is
handled as the payload part.
5. The pseudo-random pattern transmission apparatus according to
claim 1, wherein the digital line is an SDH line.
6. The pseudo-random pattern transmission apparatus according to
claim 1 wherein an error is settable in the pseudo-random pattern
in advance.
7. The pseudo-random pattern transmission apparatus according to
claim 1, wherein the pseudo-random pattern stored in the
pseudo-random pattern storage section is data having 2n-1 bits and
is changeable arbitrarily.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to an apparatus for inserting a
pseudo-random pattern into payload parts of a PPP frame and an IP
packet of PPP over SONET/SDH (POS) in an IP network used in
Internet communications and a SONET/SDH network as backbone of the
IP network and making the pseudo-random patterns in the payload
parts continuous in accordance with the PN pattern generation rule
to generate a plurality of PPP frames or IP packets at any desired
line utilization ratio
[0003] 2. Description of the Related Art
[0004] In a pseudo-random pattern generation apparatus according to
a related art, a pseudo-random pattern is temporarily stored in
memory or the like by software and in a packet preparation section,
the contents in the memory or the like are reflected on a payload
part and a flag and FCS are given and then they are put into a
packet and the packet is sent to a line.
[0005] At the time, the pattern stored in the memory has a length
of one packet and the pattern is stored in the memory by software
each time when transmission is conducted.
[0006] Thus, transmission traffic can provided on a low-speed
interface, but it is difficult to provide transmission traffic on a
high-speed interface of a POS or the like; this is a problem.
[0007] However, to eliminate a problem of memory write by software,
it is also possible to adopt a system for previously storing the
circulation portion of the PN pattern of a pseudo-random pattern
before transmission is conducted and putting given-length patterns
into packets in sequence by a packet processing section for
sending.
[0008] In such a system, the transmission traffic on a high-speed
interface can be provided, but the packet processing section needs
to reference the memory contents in sequence and thus address
management must be performed, leading to an enormous hardware scale
and an increase in costs; this is a problem.
SUMMARY OF THE INVENTION
[0009] It is therefore an object of the invention to provide a
pseudo-random pattern generation apparatus that can insert a
pseudo-random pattern into a payload part of a PPP frame or an IP
packet by software processing for transmission without using a
pseudo-random generation circuit of hardware.
[0010] To the end, there is provided a pseudo-random pattern
transmission apparatus comprising: a pseudo-random pattern storage
section (primary memory) 2 adapted to store a pseudo-random
pattern; a transmission memory 3 adapted to store a plurality of
packets which is constructed by inserting the pseudo-random pattern
in sequence into payload parts of a continuous frame of digital
signal; a software processing section 1 (CPU software processing
section) having an idle sending processing section 1-3 adapted to
calculate the number of inserted idle bytes in response to a
specified transmission rate of the digital signal; an idle sending
section 4 adapted to send an idle byte; a transmission control
section 6 (SDH transmission section) adapted to alternately execute
transmission of the plurality of packets from the transmission
memory and transmission of idle bytes from the idle sending
processing section to a digital line 7.
[0011] This configuration makes it possible to insert a
pseudo-random pattern into a payload part of a PPP frame or an IP
packet by software processing for transmission without using a
pseudo-random generation circuit of hardware.
[0012] The digital signal is an IP packet, so that the
pseudo-random pattern can be inserted into the payload part of the
IP packet for transmission to the digital line.
[0013] The digital signal is a PPP frame, so that the pseudo-random
pattern can be inserted into the payload part of the PPP frame for
transmission to the digital line.
[0014] When the digital signal is a PPP frame, the whole IP packet
contained in the PPP frame can be handled as the payload part and
the pseudo-random pattern can also be inserted into the IP packet
part for transmission to the digital line.
[0015] The digital line can also be an SDH line (PPP frame and IP
packet of PPP over SONET/SDH (POS) in SONET/SDH network).
[0016] As an error can be preset in the pseudo-random pattern, a
signal comprising the preset error inserted into a payload part is
transmitted, whereby whether or not the error can be detected can
be checked at the receiving party.
[0017] As the pseudo-random pattern stored in the pseudo-random
pattern storage section is data having 2n-1 bits and can be changed
arbitrarily, a value, such as 9, 15, or 23, can be used as n.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a drawing to show the format of a SONET/SDH frame
and the relationship between the SONET/SDH frame and a PPP
frame.
[0019] FIG. 2 is a drawing to show the formats of the PPP frame and
an IP packet.
[0020] FIG. 3 is a drawing to show a configuration of the
invention.
[0021] FIG. 4 is a drawing to show a data pattern stored in a
transmission memory.
[0022] FIG. 5 is a drawing to show a sending timing of data from an
SDH transmission section to an SDH line.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] A PPP frame of PPP over SONET/SDH (POS) in a SONET/SDH
network used in Internet communications on which the invention is
based will be discussed with reference to FIG. 1.
[0024] In FIG. 1, a SONET/SDH frame comprises three-byte SOH
(Section Overhead) and LOH (Line Overhead), a one-byte POH (Path
Overhead), and an 86-byte payload part, which has a plurality of
PPP frames each containing an IP packet.
[0025] As shown in FIG. 2A, the PPP frame comprises a flag (7E), an
address (FF), a control (03), a protocol (0021), a PPP payload, FCS
(CRC-32/16), and a flag (7E) and is 1508 bytes at the maximum.
[0026] The payload part in the PPP frame is 0 to 1500 bytes.
[0027] As shown in FIG. 2B, the IP packet comprises a version
number (ver), a header length (in 32-bit units) (HLEN), a service
type (Type of Service), a total length (in byte units) (Total
Length), a packet identifier (Identification), a fragment control
(Frags), an fragment offset (Fragment Offset), a transmission
source address (Source Address), a transmission destination address
(Destination address), an option (Option), and a payload part
(Payload).
[0028] The invention has a configuration shown in FIG. 3.
[0029] In FIG. 3, numeral 1 denotes a CPU software processing
section, numeral 2 denotes primary memory, numeral 3 denotes
transmission memory, numeral 4 denotes an idle transmission
processing section, numeral 5 denotes a memory sending processing
section, numeral 6 denotes an SDH transmission section, and numeral
7 denotes an SDH line.
[0030] The CPU software processing section 1 executes to prepare a
pseudo-random pattern by a pseudo-random pattern preparation
processing section 1-1 in response to an instruction for preparing
the pseudo-random pattern from a human interface (HMI) and stores
the prepared pseudo-random pattern in the primary memory 2.
[0031] The CPU software processing section 1 executes to prepare an
IP packet by an IP packet preparation processing section 1-2 in
response to a specification of IP payload length, an instruction
for preparing an IP header, and a specification of idle byte length
from the human interface (HMI) and stores the prepared IP packet in
the transmission memory 3.
[0032] The CPU software processing section 1 executes to calculate
the number of inserted idle bytes by a
number-of-inserted-idle-bytes calculation section 1-3 in response
to a specification of transmission rate from the human interface
(HMI) and outputs the number of inserted idle bytes to the idle
transmission processing section 4.
[0033] The pseudo-random pattern stored in the primary memory 2 is
sent to the transmission memory 3 and the pseudo-random pattern is
inserted into the payload parts of the PPP frame and the IP packet
to prepare a plurality of packets and the packets are stored in the
transmission memory 3.
[0034] The PPP frame and the IP packet with the payload parts into
which the pseudo-random pattern is inserted are transmitted through
the memory sending processing section 5 from the SDH transmission
section 6 to the SDH line 7 together with output of the idle
transmission processing section 4.
[0035] In packet sending in the invention, data in which a PN
pattern is completed is prepared in the primary memory 2 by
software processing to prepare the pseudo-random pattern.
[0036] The data is repeatedly sent from the memory, whereby the
continuity of the PN pattern can be assured.
[0037] In the invention, pseudo-random patterns of 32 cycles are
used. The reason is obtained from the following conditions:
[0038] The pseudo-random pattern consists of 2n-1 bits (n is
determined by Recommendation and is 9, 15, 23, etc., for
example).
[0039] In PPP over SDH, an octet-synchronous data structure is
adopted and thus bits of eight cycles are required.
[0040] Since the IP packet takes a four-byte boundary structure,
bits of four cycles are required.
[0041] Next, a packet preparation procedure in the invention will
be discussed.
[0042] To being with, for the CPU software processing section
1,
[0043] template of header part of frame or packet is specified;
[0044] payload length of frame or packet is specified; and
[0045] the number of idle data bytes (containing the flag sharing
byte) between frames or packets is specified from the human
interface (HMI) in response to an instruction for preparing
pseudo-random pattern.
[0046] In response to the specification from the human interface
(HMI), the process of inserting the pseudo-random pattern stored in
the primary memory 2 into the payload part every given length,
performing IP packet header and FCS calculation to prepare a
packet, and storing the packet in the transmission memory 3 is
repeated.
[0047] Consequently, the data stored in the transmission memory 3
is prepared as shown in FIG. 4.
[0048] FIG. 4 shows the data prepared and stored in the
transmission memory 3 in the invention. Basically, the data
comprises repetitions of IP header part (1), IP payload part into
which pseudo-random pattern is inserted (2), and idle part (3).
[0049] Next, a procedure of inserting the pseudo-random pattern
into the IP payload part will be discussed.
[0050] In FIG. 4, (1) indicates template of header part of frame or
packet specified from the human interface (HMI).
[0051] In FIG. 4, (2)-1 indicates pseudo-random pattern having the
payload length specified from the human interface (HMI) (The
pseudo-random pattern is read in sequence by the payload length
specified from the human interface (HMI) at a time.) In FIG. 4, (3)
indicates as many idle bits as the number of idle data bytes
(containing the flag sharing byte) between frames or packets
specified from the human interface (HMI).
[0052] In FIG. 4, (1) following (3) is the same as the first (1)
and indicates template of header part of frame or packet specified
from the human interface (HMI).
[0053] In FIG. 4, (2)-2 is the same as (2)-1 and indicates
pseudo-random pattern of payload length specified from the human
interface (HMI) and the pseudo-random pattern is a portion read
following (2)-1 from the primary memory 2.
[0054] As the process is repeated, (2)-last in FIG. 4 indicates the
portion of the remainder of the pseudo-random pattern divided by
the payload length specified from the human interface (HMI).
[0055] Therefore, (2)-1, (2)-2, . . . (2)-last results in
(2)-1+(2)-2+ . . . +(2)-last=32-cycle pseudo-random pattern
(bits).
[0056] Next, a procedure of the SDH transmission procedure 6 for
transmitting the data as shown in FIG. 4, stored in the
transmission memory 3 to the SDH line will be discussed with
reference to FIG. 5.
[0057] To begin with, the sending percentage of the whole frame or
packet (the percentage occupied by the whole frame or packet
assuming that the total number of bits of SONET/SDH payload is
100%) is specified from the human interface (HMI).
[0058] Next, as shown in FIG. 5, the number-of-inserted-idle-bytes
calculation section 1-3 calculates how many bytes of idle data are
to be sent between transmission memories based on the total number
of idle data bytes (containing the flag sharing byte) between the
frames or packets stored in the transmission memory 3 and the
sending percentage of the whole frame or packet specified from the
human interface (HMI), and outputs the number of idle bytes through
the idle transmission processing section 4 to the SDH transmission
section 6.
[0059] Whenever the SDH transmission section 6 transmits data read
from the transmission memory 3, it transmits as many idle bytes as
the number of idle bytes calculated by the
number-of-inserted-idle-bytes calculation section 1-3 to the SDH
line 7 consecutively.
[0060] As the process is repeated, the packet with the payload
containing the pseudo-random pattern is sent to the SDH line 7 at
the transmission rate specified on the human interface (HMI).
[0061] In the description given above, the pseudo-random pattern is
inserted into the payload part in the IP packet; however, it is
also possible that the whole IP packet forming a part of the PPP
packet is handled as payload into which the pseudo-random pattern
is inserted.
[0062] To transmit the pseudo-random pattern, it is also possible
that a predetermined error is preset in the pseudo-random pattern,
whereby whether or not the setup error can be detected at the
receiving party is determined.
[0063] According to a first aspect of the invention there is
provided a pseudo-random pattern transmission apparatus comprising:
a pseudo-random pattern storage section 2 (primary memory) adapted
to store a pseudo-random pattern; a transmission memory 3 adapted
to store a plurality of packets which is constructed by inserting
the pseudo-random pattern in sequence into payload parts of a
continuous frame of digital signal; a software processing section 1
(CPU software processing section) having an idle sending processing
section 1-3 adapted to calculate the number of inserted idle bytes
in response to a specified transmission rate of the digital signal;
an idle sending section 4 adapted to send an idle byte; a
transmission control section 6 (SDH transmission section) adapted
to alternately execute transmission of the plurality of packets
from the transmission memory and transmission of idle bytes from
the idle sending processing section to a digital line 7. Whereby,
the pseudo-random pattern can be inserted into the payload part of
the PPP frame or the IP packet by software processing for
transmission without using a pseudo-random generation circuit of
hardware.
[0064] According to a second aspect of the invention, the digital
signal is an IP packet, so that the pseudo-random pattern can be
inserted into the payload part of the IP packet for transmission to
the digital line.
[0065] According to a third aspect of the invention, the digital
signal is a PPP frame, so that the pseudo-random pattern can be
inserted into the payload part of the PPP frame for transmission to
the digital line.
[0066] According to a fourth aspect of the invention, when the
digital signal is a PPP frame, the whole IP packet contained in the
PPP frame can be handled as the payload part and the pseudo-random
pattern can also be inserted into the IP packet part for
transmission to the digital line.
[0067] According to a fifth aspect of the invention, the digital
line can also be an SDH line (PPP frame and IP packet of PPP over
SONET/SDH (POS) in SONET/SDH network).
[0068] According to a sixth aspect of the invention, as an error
can be preset in the pseudo-random pattern, a signal comprising the
preset error inserted into a payload part is transmitted, whereby
whether or not the error can be detected can be checked at the
receiving party.
[0069] According to a seventh aspect of the invention, as the
pseudo-random pattern stored in the pseudo-random pattern storage
means is data made up of 2n-1 bits and can be changed arbitrarily,
a value, such as 9, 15, or 23, can be used as n, and the
pseudo-random pattern can be processed without adding any
hardware.
* * * * *